Nicotine by itself may harm embryos, even without the toxins from burning tobacco, shows a lab-based study.

Nicotine itself may be damaging to embryos, even without the toxins generated by burning tobacco, according to US research.

The scientists exposed embryoid bodies – ‘simulated’ embryos composed of groups of stem cells that give rise to the brain, heart, liver, blood vessels, muscles and other organs – to a growth fluid dosed with nicotine for three weeks.

“Embryoid bodies are 3D embryo-like structures representative of a stage of development shortly after implantation, generally before a woman knows she is pregnant,” The University of Melbourne’s Dr Alexandra Harvey told the AusSMC.

The researchers found nicotine killed off cells, caused growth defects, increased levels of damaging molecules, and interfered with communication between cells and with normal cell functioning.

Nicotine affects development of tissues

The University of Adelaide’s Dr Ian Musgrave explained that the researchers looked at gene activity in single cells taken from the nicotine-exposed embryoids, providing “a snapshot of how nicotine influences the development of these tissues, and insight into how nicotine exposure translates into low birthweight, sudden infant death syndrome, craniofacial abnormalities and heart disease”.

“Everyone knows that smoking when pregnant can lead to problems with the baby’s growth and long-term metabolic adverse effects in the children born to smoking mothers,” UQ’s Associate Professor Gino Pecoraro told the Centre. “The mothers also suffer from higher rates of miscarriage and birth prematurity as well as heart and lung issues.”

But the new research suggests it’s not just cigarette-smoking mums-to-be who are harming their unborn babies; those who have ditched the smokes and use nicotine replacement therapies (NRTs) or nicotine e-cigarettes may also be damaging the health of their unborn children.

Dr Harvey told the AusSMC that the study should worry women who smoke before they know they are pregnant – around 12 per cent of Australian women – particularly those that switch to NRTs or e-cigs.

Many women will have believed that switching represented a safe alternative to smoking which would not harm their babies.

But the study “highlights that even brief exposure to nicotine at a critical developmental stage is sufficient to induce adverse changes,” said Dr Harvey.

Lab results may not reflect environment inside a human body

However, the researchers themselves concede that these embryoid bodies, grown in the lab, don’t necessarily reflect the environment inside the body of a pregnant woman, and Dr Musgrave pointed out that the levels of nicotine they exposed the embryoid bodies to were very high.

“The authors used concentrations of nicotine around 30 times or more higher than would be found in a mother’s blood, whether smoking, using nicotine patches or vaping nicotine-containing liquids,” he said.

But all the experts agreed that the take-home message for women who are pregnant, or think they may become pregnant, is that it’s best to avoid nicotine in all its forms to increase the chances of a healthy pregnancy.

About the Author

Joseph Milton
Joe Milton is an evolutionary biologist who, after studying the evolution of plants for ten years at various Scottish universities, made a move into journalism. Since then he has written for the Financial Times, Nature and New Scientist, among others. Joe joined the London Science Media Centre in 2010, where he was Senior Press Officer for Mental Health, before taking up the position of Senior Media Officer at the Australian Science Media Centre in July 2012.

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